You can cut the flank steak into 2-inch pieces or longer, thinner strips along the grain.

Mix together the soy sauce and Worcestershire sauce with grated ginger, red pepper flakes, red pepper flakes, honey, minced garlic, and hot Chinese mustard in a medium bowl. Mix well and place in a bowl.

Sesame oil can be added to a medium-sized cast iron pan on medium heat.

When the oil has boiled, add the flank steak sliced in one layer. Allow it to brown well for about 1-2 minutes, without turning it. Then, use tongs to flip the beef over and brown it for 2-3 more minutes.

Turn down heat to low-medium, and then add the sauce to a saucepan. Stir the mixture and allow it to simmer for 5 minutes on low heat until it reduces by half. The sauce will then become sticky.

Serve the beef with rice. Serve the beef over rice with chopped green onions, sesame seeds and garnish.